这个教程里的一个演示，问题是如何声明unit target?
globals
hashtable HT = null
endglobals
function Init takes nothing returns nothing
call FlushParentHashtable( HT )
set HT = InitHashtable()
endfunction
function Damage_Act takes nothing returns boolean
local integer parentKey = GetHandleId( GetTriggeringTrigger() )
local unit source = LoadUnitHandle( HT, parentKey, 1 )
local unit target = LoadUnitHandle( HT, parentKey, 2 )
call FlushChildHashtable( HT, parentKey )
call TriggerRemoveCondition( GetTriggeringTrigger(), LoadTriggerConditionHandle( HT, parentKey, 3 ) )
call DestroyTrigger( GetTriggeringTrigger() )
set source = null
set target = null
return false
endfunction
function Damage takes unit source, unit target returns nothing
local trigger t = CreateTrigger()
local integer parentKey = GetHandleId( t )
local boolexpr cond = Condition( function Damage_Act )
call SaveUnitHandle( HT, parentKey, 1, source )
call SaveUnitHandle( HT, parentKey, 2, target )
call TriggerRegisterUnitEvent( t, target, EVENT_UNIT_DAMAGED )
call SaveTriggerConditionHandle( HT, parentKey, 3, TriggerAddCondition( t, cond ) )
set t = null
set cond = null
endfunction